Employing DGS structures in dual-band antennas for MIMO applications with high port isolation

This letter investigates the effect of mutual coupling on the operation of a dual-band MIMO antenna system. A rectangular codirectional split ring resonator-type (RCSRR) defected ground structure (DGS) is designed to isolate the antennas and reduce the influence of coupling on radiation characteristics. This compact dual-band DGS structure consists of two codirectional split rings resonator and locates between two patches, and the dimension of each ring controls the corresponding resonant frequency. Two multiantenna prototypes are fabricated and experimentally evaluated. Measurement results confirm the improvement of isolation between the antennas at the radiation frequency of 2.3/4 GHz when the DGS is utilized. The measured isolation of antenna with DGS has obviously improved than that of the original one in two operating bands. The predicted results agreed very well with measured data.